Pneumonia (nu-MO-ne-ah) is an infection in one or both of the lungs. Many germs—such as bacteria, viruses, and fungi—can cause pneumonia.
The infection inflames your lungs' air sacs, which are called alveoli (al-VEE-uhl-eye). The air sacs may fill up with fluid or pus, causing symptoms such as a cough with phlegm (a slimy substance), fever, chills, and trouble breathing.
Pneumonia and its symptoms can vary from mild to severe. Many factors affect how serious pneumonia is, such as the type of germ causing the infection and your age and overall health.
Pneumonia tends to be more serious for:
- Infants and young children.
- Older adults (people 65 years or older).
- People who have other health problems, such as heart failure, diabetes, or COPD (chronic obstructive pulmonary disease).
- People who have weak immune systems as a result of diseases or other factors. Examples of these diseases and factors include HIV/AIDS, chemotherapy (a treatment for cancer), and an organ transplant or blood and marrow stem cell transplant.
Pneumonia is common in the United States. Treatment for pneumonia depends on its cause, how severe your symptoms are, and your age and overall health. Many people can be treated at home, often with oral antibiotics.
Children usually start to feel better in 1 to 2 days. For adults, it usually takes 2 to 3 days. Anyone who has worsening symptoms should see a doctor.
People who have severe symptoms or underlying health problems may need treatment in a hospital. It may take 3 weeks or more before they can go back to their normal routines.
Fatigue (tiredness) from pneumonia can last for a month or more.